Lessons learned: The nipples were too short so I wasn't able to use the locknuts. As a result, the bulkhead wasn't as tight of a fit as I would have liked. Occasionally I'll get a drip or two leaking past the bulkhead assembly. Not a big deal, but I'd recommend using a slightly longer nipple, perhaps part #4830K172 from http://www.mcmaster.com/ as I think this would probably provide a better seal.

Assemble the parts per the diagram below for both your hot liquor tank (HLT) and your mashtun. You'll also want to install some kind of false bottom in your mashtun. I use a section of stainless steel mesh (from the outside of a stainless steel water supply line) attached to a 1/2 male threaded copper fitting. The copper fitting is screwed into the coupling and the stainless steel mesh is attached to it.

After you figure in shipping costs, you should be able to build these for pretty close to $40 each or $80 for the whole system. Most of the comparable commercially available systems sell for about $180 and up, so there's potential to save quite a bit of money by building this yourself.